In many agricultural operations, such as tilling, planting, fertilizing and the like, it is common to use a tractor or a separate tow frame connected to a tractor to tow a tool bar assembly over the surface of the farm field. The tool bar assembly is elongated and extends from side-to-side in a lateral or transverse direction behind the tractor or tow frame. A plurality of agricultural tools that perform some type of agricultural operation on the ground are carried on the tool bar assembly and are spaced apart across the width of the tool bar assembly. For example, when tilling soil, the tools comprise blades, rotary coulters and other known devices that break up the soil in preparation for planting. As the tractor or tow frame is propelled forwardly over the farm field in a forward direction, the tools carried on the tool bar assembly act in a wide swath dependent upon the width of the tool bar assembly and how many tools are carried on the tool bar assembly. In a soil tilling operation, the type and spacing of the tools carried on the tool bar assembly determines whether the soil is being tilled in a zone tillage method in which untilled strips are left in the swath or whether the entire swath is being tilled from side to side without leaving any untilled strips in the swath.
To enhance productivity, some tool bar assemblies are very wide. For example, a tool bar assembly having a 60 foot width would be considered a wide tool bar assembly. Thus, as the tractor makes a single pass over the farm field, the soil can be tilled, or the crop can be planted, or the ground can be fertilized, over a 60 foot swath. Thus, the farm field can be worked more quickly than if a tool bar assembly having only a 30 foot width is used. The tractor or tow frame need make only half as many passes over the farm field using a 60 foot tool bar assembly as opposed to a 30 foot tool bar assembly. This saves the farmer considerable time and expense.
While very wide tool bar assemblies are desirable from a productivity standpoint, they present various problems. Such tool bar assemblies have to be made in multiple sections that can be folded up. This is needed to reduce the width of the tool bar assembly to something that is not a great deal wider than the width of the tractor to allow the tractor and the trailing tool bar assembly to be transported on a road and for compact storage of the tool bar assembly. However, it can be difficult to fold a wide tool bar assembly into a compact form without having the folded tool bar assembly extend unduly high in a vertical direction, thereby posing height clearance issues, or unduly long in a fore and aft longitudinal direction in which the tool bar assembly may extend along the entire front to back length of the tractor, thereby making operator access to the cab of the tractor more difficult or blocking the vision of the operator to the sides of the tractor.
In addition, with a wide tool bar assembly having pivotal wings that fold up, the weight of the wings must be adequately supported when the tool bar assembly is both unfolded and folded. This is often done by using long support arms or stringers that extend out between the pivotal wings and a central portion of the tool bar assembly or some portion of the frame on which the central portion is carried. However, the need for such stringers only complicates the task of folding and unfolding the tool bar assembly as such stringers or support arms must themselves be folded, or at least pivoted out of the way, as the pivotal wings of the tool bar assemblies are folded up.
Accordingly, it would be an advance in the agricultural art to provide a wide swath tool bar assembly that can be folded up into a compact form that is neither unduly high nor unduly lengthy relative to the tractor or other frame on which the tool bar assembly is carried.